Ecology is the study of interacting biological systems and their nonliving support. Ecologists study food chains, cooperation and competition between species, and special adaptations to environmental niches. Modern ecology is especially concerned with the impact of the human species on the rest of nature, both in relation to accelerating demands on the natural world by highly exploitative technology and in relation to the exponentially increasing number of humans who are making these demands. Human population ecology deals with problems of famine, pollution, disease, and even the violence associated with overpopulation pressures. This article deals primarily with North American Mennonites. The rise of a strong ecology movement in Europe, especially the "Greens Party" in Germany, and Mennonite responses to this and similar developments in The Netherlands, are not included here.

Rachel Carson established the case for the environmental movement in her 1962 bestseller, Silent spring. She contended, among other things, that either we abandon the use of the new pest-killing technologies such as DDT and DDD, or we will lose a significant segment of the natural world, including the songbirds of spring. She concluded her book with the assertion that "control of nature" was an arrogant concept, "born of the Neanderthal age of biology and philosophy, when it was supposed that nature exists for the convenience of man" (Carson, p. 261).

The second major tract of the environmental movement was Paul Ehrlich's The population bomb, published first in 1968. The book contained dramatic and convincing warning on population growth.

The controversy over population control and limitations of world resources heated up considerably with the prescription of "triage" by William and Paul Paddock in their 1967 book, Famine, 1975! They proposed that only those countries which had a good chance of continued survival should be helped with food aid. Those countries, such as Haiti, which were beyond help, should be left to starve. Garrett Hardin contributed to the harshness of the debate with his observations on the "tragedy of the commons" and "lifeboat ethics." Hardin contended that greed and shortsightedness led to overgrazing the commons, that part of the ecosystem which is free and open for everyone's use but for which no one accepted responsibility for its protection. He used an analogy to express his view of the fortunate and unfortunate: the occupants of a lifeboat filled to capacity who fight off drowning people surrounding the boat out of fear that additional occupants would swamp the boat and doom those in it as well as outside it. The principle arose directly from ecology's concept of carrying capacity; if an ecosystem is taxed beyond its productive ability, the whole system may crash, often with little warning.

An important contribution to the ethical and religious debate was the article published in Science in 1967 by Lynn White, Jr., called "The historical roots of our ecological crisis." White repeated Rachel Carson's contention that the Western Christian tradition fostered a "control of nature" philosophy.

Responses among Mennonites to the ecological crisis were varied. Many farmers resented the curbs on pesticides that were enacted following the warning by Rachel Carson; they disagreed strongly with her revered status among environmentalists. Mennonites reacted quickly and compassionately to urgent calls for food in the famine situations of the 1970s, rejecting the triage and lifeboat proposals. Hundreds of young agriculturists, nutritionists, and teachers responded to Mennonite Central Committee efforts at food development projects throughout the world.

The Green Revolution rice and wheat varieties of the early 1970s helped prevent the great famine predicted by the Paddocks, but many farmers, especially in Africa, were unable to participate in the relatively high technology which accompanied the Green Revolution crops.

Mennonite colleges put more emphasis on ecological and world hunger topics. Eastern Mennonite College designed all-school seminars in 1972 and 1976 on ecological and hunger concerns. Courses such as "Food and population" were introduced into the curriculum. Eastern Mennonite College, Bethel College, and Goshen College all began programs in agricultural development which graduated more than a dozen students a year in the 1980s.

Doris Janzen Longacre's book, Living more with less, was published in 1980, following the highly successful More-with-less cookbook. Simple living was promoted as a way to "cherish the natural order" (Longacre, p. 42). Willard Swartley's "Biblical sources of stewardship," in The earth is the Lord's makes an eloquent plea to accept the world's resources as a common possession of all humanity (Jegen and Manno, 22-43).

Ron Sider's book Rich Christians in an age of hunger, continues its strong critique of injustice and complacency with its second edition. Most of these Mennonite and Brethren in Christ responses to the ecological crisis draw heavily from simple life positions advocated by E. F. Schumacher in his popular Small is beautiful treatise, first published in 1973.

Kansas farmers, with help from Mennonite Central Committee, organized a significant newsletter, Swords into plowshares, which dealt with ecological and justice concerns in relation to land and agriculture. Numerous conferences were held in Kansas, the Midwest, Ontario, and at Laurelville (Pa.) Church Center on agriculture and ecology, with concerns in the late 1970s and early 1980s dealing more directly with financial crisis among Mennonite farmers. Mennonites in Oregon and Pennsylvania were also active in preserving agricultural land through legal procedures, recognizing that the Amish were probably the leaders in protecting land from developers.

A profound ecological development in 1974 and 1977 was the dramatic rise in fuel costs. Mennonites responded in a way similar to that of the general public. Many households turned to wood for fuel; at least three Mennonite-owned wood stove factories flourished for several years in Harrisonburg, Va. (Riteway, Sierra, and Shenandoah). Mennonites in Kansas and Ontario organized solar collector manufacturing concerns. With the drop of fuel prices in the mid-1980s, these businesses closed or greatly reduced their production. A recycling business, Earthkeepers, started in the mid-1970s at Eastern Mennonite College and continued uninterrupted by the erratic market cycle. The paper and glass recycling project is currently managed by a group of business students and enjoys excellent support in the community. Recycling has also been popular in other communities, often with the assistance and encouragement of local Mennonites.